7.7 - Xylem & Phloem Flashcards
Why plants need transport systems Functions and adaptations of xylem tissue Functions and adaptations of phloem tissue (7 cards)
1
Q
Why do plants need transport systems?
Give 3 reasons
A
- Multicellular with a low SA:Vol
- Diffusion too slow to meet their metabolic needs
- Substances must be moved over long distances
2
Q
What are the two main transport tissues in plants?
A
- Xylem
- phloem
3
Q
What does xylem tissue transport?
A
Water and mineral ions
4
Q
How are xylem vessels adapted for transport?
4 ways
A
- Elongated hollow tubes without end walls
- lack organelles
- lignin thickened walls
- non-lignified pits (allow movement of water/ions in/out vessels)
5
Q
What does phloem tissue transport?
A
Sugars and amino acids
6
Q
How are sieve tube elements adapted for transport?
4 ways
A
- Connected end-to-end to form tubes
- sieve plates have pores
- lack nuclei & most organelles
- thin cytoplasm
7
Q
How are companion cells adapted for transport?
2 ways
A
- They are connected to sieve tube elements through pores (plasmodesmata).
- The cytoplasm contains a large nucleus, many mitochondria to release energy for the active transport of substances through the sieve tube elements, and many ribosomes for protein synthesis.
